Liquid fertilizing compositions

ABSTRACT

Liquid fertilizer compositions and methods of making liquid fertilizer compositions are set forth herein. In one embodiment, a liquid fertilizing composition includes an aqueous ammonium chloride solution and an acrylamide copolymerized with acrylic acid. In another embodiment, a liquid fertilizing composition includes an aqueous ammonium chloride solution having a pH between 6.5 and 8.5 and an anionic polyacrylamide. The anionic polyacrylamide is present between 0.5 and 1.0 percent by weight. In yet another embodiment, a liquid fertilizing composition consists essentially of at least 16.5 percent by weight ammonium chloride, between 0.5 and 1.0 percent by weight acrylamide copolymerized with acrylic acid or salt thereof, an effective amount of corrosion inhibitor, and water.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/690,720, filed Jan. 20, 2010 now U.S. Pat. No. 7,985,276,which in turn claims the benefit of priority as a continuation-in-partof U.S. patent application Ser. No. 12/060,644, filed Apr. 1, 2008 andissued as U.S. Pat. No. 7,674,312, which in turn claims the benefit ofpriority to U.S. Provisional Patent Application No. 60/971,635, filedSep. 12, 2007; the benefit of priority to each of these filings isaccordingly claimed, and the contents of each of these filings areincorporated herein by reference.

BACKGROUND

Fertilizers are often provided to plants to promote healthy growth.Liquid fertilizer compositions and methods of making liquid fertilizercompositions are set forth herein.

SUMMARY

In one embodiment, a liquid fertilizing composition contains ammoniumchloride and an anionic polyacrylamide. The anionic polyacrylamidepreferably contains at least one monomeric unit of acrylamide and atleast one monomeric unit of acrylic acid or salt thereof, and theanionic polyacrylamide is prepared by copolymerization of monomericacrylamide and monomeric acrylic acid or salt thereof. By way ofexample, one such anionic polyacrylamide is KemGuard 5870 made by KemiraChemicals, Inc. (Kennesaw, Ga., U.S.).

In another embodiment, a liquid fertilizing composition contains anaqueous ammonium chloride solution having a pH between 6.5 and 8.5 andan anionic polyacrylamide comprising at least one monomeric unit ofacrylamide and at least one monomeric unit of acrylic acid or saltthereof. The anionic polyacrylamide is present between 0.5 and 1.0percent by weight.

In yet another embodiment, a liquid fertilizing composition consistsessentially of at least 16.5 percent by weight ammonium chloride,between 0.5 and 1.0 percent by weight anionic polyacrylamide, aneffective amount of corrosion inhibitor, and water. The anionicpolyacrylamide includes at least one monomeric unit of acrylamide and atleast one monomeric unit of acrylic acid or salt thereof, and theanionic polyacrylamide is prepared by copolymerization of acrylamide andacrylic acid or salt thereof.

DETAILED DESCRIPTION

The application of compositions containing chloride (Cl⁻) ions is knownto benefit crops in a variety of ways. Among other things, the uptake ofchloride ions by crops has been shown to increase crop yield, reducesusceptibility to disease, reduce disease damage, accelerate plantdevelopment, improve kernel weight, and reduce late-season lodging.Sources of chloride ion commonly used as fertilizers include potassiumchloride, magnesium chloride, and calcium chloride, though each of thesesources has disadvantages.

In searching for an alternative to these sources, aqueous ammoniumchloride solutions having between 16.5 and 30 percent by weight ofammonium chloride, and preferably 24 to 25 percent by weight of ammoniumchloride, have been tested as fertilizers. These ammonium chloridesolutions experienced substantial problems with salting-out.“Salting-out” is used herein to indicate the formation of precipitate.However, after extensive testing, it was discovered that combining oneor more dispersants selected from anionic polyacrylamides, having thegeneral formula:

with the aqueous ammonium chloride solution reduced or eliminatedsalting-out. A product having CAS number 25987-30-8 and marketed asCyanamer® P-70 by CYTEC Industries Inc. of West Paterson, N.J. is onesuch dispersant. This product is referred to herein as CAS 25987-30-8 oras “P-70.”, and it should be understood that the chemical composition,and not the manufacturer or marketer, is of interest.

Other suitable anionic polyacrylamides have been found to include, forexample: Cyanamer® P-94 by CYTEC Industries Inc. of West Paterson, N.J.;APS 600 Series and APS 700 Series marketed by Applied Polymer Systems ofWoodstock, Ga.; Soilfix IR, Percol 710, Percol 790, DP10-0434, andSoilfix LDP marketed by Ciba Specialty Chemicals, Inc. of Suffolk, Va.;Sioloc-PAM marketed by Hercules Environmental, Inc. of Doraville, Ga.;HydroPAM marketed by Stockhausen, Inc. of Greensboro, N.C.; CFM 2000PAM; Bluwat Anionic Polyacrylamide marketed by Yixing Bluwat ChemicalsCo., Ltd. of China; and CAS 25085-02-3; as well as derivatives andcombinations thereof.

Table 1 shows the temperature at which the ammonium chloride solutioncombined with various amounts of CAS 25987-30-8 salted-out. In Table 1,solid conditions are marked as such, and “X” represents any presence ofprecipitate in which the entire composition was not completely solid.The compositions in Table 1 included 24 to 25 percent by weight ammoniumchloride, the indicated amount of CAS 25987-30-8, and water; the pH ofthe compositions in Table 1 was 6.0.

TABLE 1 weight % CAS 25987-30-8 40° F. 36° F. 32° F. 30° F. 20° F. 15°F. 10° F. 0.75 X X X X 0.50 X X X X X X 0.375 X X X X solid solid 0.19 XX X X solid solid solid 0 X X X solid solid solid solid

As shown in Table 1, adding 0.75 percent by weight of CAS 25987-30-8 tothe ammonium chloride solution allowed the product to be used attemperatures as low as 32 degrees Fahrenheit. Ammonium chloride with0.75 percent by weight P-70 has been used and sold by the presentinventor with great success since 2004. Nevertheless, problems havearisen. Specifically, the product is corrosive and can destroy storagetanks.

To reduce the corrosivity of the composition, many corrosion inhibitorswere tested, resulting in varying, but generally unsuitable, degrees ofsuccess. It was then determined that raising the pH of the ammoniumchloride solution would alone reduce its corrosivity, and that adding acorrosion inhibitor in addition to raising the pH could also bebeneficial. More particularly, raising the pH from approximately 6.0 tobetween 6.5 and 8.5, and preferably between 7.5 and 8.5, resulted inreduced corrosivity. Adding less than 0.1 percent by weight, andpreferably approximately 0.05 percent by weight, of a corrosioninhibitor, such as NITROSolve™ 220, marketed by NALCO Company ofNaperville, Ill., worked well in conjunction with raising the pH, asdiscussed above. NITROSolve™ 220 contains glycerol and a proprietaryorganic sulfonate. Effective amounts of other corrosion inhibitors(i.e., sufficient amounts to inhibit corrosion without significantlyaltering the fertilizing properties of the composition) may also beacceptable in conjunction with raising the pH as discussed above. Suchcorrosion inhibitors include, but are not limited to: products known asNITROSolve™ 330 and Protexo, both marketed by NALCO Company ofNaperville, Ill.; P-35 by CYTEC Industries Inc. of West Paterson, N.J.;urea (46-0-0); corn steep liquor; as well as derivatives andcombinations thereof.

Adding ammonia to the ammonium chloride solution is an effective way toraise the pH, although other methods would also be appropriate,including adding aqua ammonia and/or sodium hydroxide, for example.Adding ammonia may also increase the nitrogen (i.e., ammonia nitrogen)level of the fertilizer, from, for example, 5.5 percent to 6 percent.Even without adding ammonia to increase the pH, the ammonium chloridemay provide a level of ammonia nitrogen, such as, for example, 5.5percent by weight. Increased nitrogen levels have been shown to benefitcrops.

Ammonium chloride may be obtained from waste sources, such as from spentbatteries, or from the electronics industry where it is used to cleansoldering irons, for example. Ammonium chloride obtained from wastesources will vary in pH depending upon the source, and will most likelycontain impurities. Low levels of impurities may be insignificant to thepresent aqueous fertilizer compositions so long as the impurities arenot present in a concentration that is unsafe for use in fertilizer.Alternatively, ammonium chloride with a standardized purity rating maybe obtained directly from a chemical supplier.

The aqueous ammonium chloride fertilizer with increased pH and,optionally, one or more corrosion inhibitors is much less corrosive thanan aqueous ammonium chloride fertilizer having a pH at or below 6. Thecomposition having increased pH may thus allow the fertilizer to besafely stored in steel tanks and increase the useful life of applicators(i.e., sprayers).

As set forth in U.S. Pat. No. 7,674,312, raising the pH of the ammoniumchloride solution was also found to have an unexpected synergic effecton the fertilizer's salt-out properties. Table 2 shows the temperatureat which the ammonium chloride solution combined with various amounts ofCAS 25987-30-8 salted-out when the pH of the ammonium chloride solutionwas raised from approximately 6.0 (Table 1) to approximately 7.8. InTable 2, solid conditions are marked as such, and “X” represents anypresence of precipitate in which the entire composition is notcompletely solid. The compositions in Table 2 included 24 to 25 percentby weight ammonium chloride, the indicated amount of CAS 25987-30-8, andwater; the pH of the compositions in Table 2 was 7.8. A corrosioninhibitor was not present in the compositions of Table 1 or thecompositions of Table 2.

TABLE 2 weight % CAS 25987-30-8 40° F. 36° F. 32° F. 30° F. 20° F. 15°F. 10° F. 0.75 X 0.50 X X X 0.375 X X X 0.19 X X X solid 0 X X X X solidsolid

As shown in Table 2, adding 0.75 percent by weight of CAS 25987-30-8 toan ammonium chloride solution with a pH of approximately 7.8unexpectedly allowed the product to be used at temperatures above about10 degrees Fahrenheit.

Because of the substantially lowered salt-out temperature, the aqueousammonium chloride fertilizer could be applied from the fall through theearly spring, which are times when the prior aqueous ammonium chloridefertilizer with a pH of approximately 6.0 could not have beeneffectively applied. Applying the fertilizer in the fall through earlyspring may increase yield between 7 and 12 bushels per acre,substantially increasing revenue per acre. Similarly, the surprisinglylow salt-out temperature may allow the aqueous ammonium chloridefertilizer to be applied in areas of colder climate with beneficialresults.

It is also disclosed herein that, by altering the composition ofacrylamide and acrylate in the anionic polyacrylamide, a substantiallylowered salt-out temperature can be achieved without raising the pH ofthe aqueous ammonium chloride fertilizer. More particularly, commercialanionic polyacrylamide (e.g., CAS 25987-30-8 marketed as Cyanamer® P-70)is typically made by hydrolyzing a polymerized acrylamide with peroxideto obtain the acrylate functionality. If, instead, the anionicpolyacrylamide (which can still have a CAS number 25987-30-8, forexample) is made by copolymerizing acrylamide with acrylic acid or saltthereof, then a more controlled acrylamide/acrylate pattern may result.Such an anionic polyacrylamide is marketed as KemGuard 5870 and Colloid237 with a CAS number 25987-30-8 by Kemira Chemicals, Inc., which has anoffice in Kennesaw, Ga., and is referred to as “KemGuard 5870” in thisdisclosure. Combining KemGuard 5870 with an aqueous ammonium chloridesolution has surprisingly reduced the salt-out temperature well beyondthe salt-out temperature of the traditional combination of aqueousammonium chloride solution and P-70. Moreover, while the traditionalcombination containing ammonium chloride and P-70 works best at a higherpH of between 6.5 and 8.5 (and preferably between 7.5 and 8.5), the newcomposition containing ammonium chloride and KemGuard 5870 works equallywell across a broader spectrum of pH, for example, from pH 4 up to 8.5,if not higher. As such, the costs of raising the pH may be avoided bycombining the aqueous ammonium chloride solution with the KemGuard 5870,and improved salt-out temperatures may nevertheless be obtained. Theanionic polyacrylamide prepared by copolymerization of acrylamide andacrylic acid or salt thereof may, for example, have a concentration thatis between 0.5 and 1.0 percent by weight of the composition, and theammonium chloride may have a concentration of at least 16.5 percent byweight of the composition.

If desired, such as to reduce corrosivity, a corrosion inhibitor may beadded to the aqueous ammonium chloride solution having the anionicpolyacrylamide prepared by copolymerization of acrylamide and acrylicacid or salt thereof, and/or the pH of the solution may nevertheless beincreased; these measures are not necessary to reduce the salt-outtemperature of the liquid fertilizing composition, however.

Those skilled in the art appreciate that variations from the specifiedembodiments disclosed above are contemplated herein and that thedescribed test results are not limiting. The description should not berestricted to the above embodiments or test results, but should bemeasured by the following claims.

What is claimed is:
 1. A liquid fertilizing composition, comprising:ammonium chloride; and an anionic polyacrylamide comprising at least onemonomeric unit of acrylamide and at least one monomeric unit of acrylicacid or salt thereof, wherein the anionic polyacrylamide is prepared bycopolymerization of acrylamide and acrylic acid or salt thereof.
 2. Thecomposition of claim 1, further comprising a corrosion inhibitor.
 3. Thecomposition of claim 2, wherein the corrosion inhibitor includes atleast one member selected from the group consisting of: (a) urea; (b)corn steep liquor; (c) glycerol; and (d) organic sulfonate.
 4. Thecomposition of claim 1, wherein the anionic polyacrylamide has CASnumber 25987-30-8.
 5. The composition of claim 1, wherein the anionicpolyacrylamide has a concentration between 0.5 and 1.0 percent by weightof the composition.
 6. The composition of claim 1, wherein the pH of thecomposition is between 4 and 8.5.
 7. The composition of claim 1, whereinthe pH of the composition is between 6 and 8.5.
 8. A liquid fertilizingcomposition, comprising: an aqueous ammonium chloride solution having apH between 6.5 and 8.5; and an anionic polyacrylamide comprising atleast one monomeric unit of acrylamide and at least one monomeric unitof acrylic acid or salt thereof; wherein the anionic polyacrylamide ispresent in said composition between 0.5 and 1.0 percent by weight;wherein the anionic polyacrylamide is prepared by copolymerization ofacrylamide and acrylic acid or salt thereof.
 9. The composition of claim8, further comprising an effective amount of a corrosion inhibitor. 10.The composition of claim 8, further comprising a corrosion inhibitor,and wherein: the corrosion inhibitor is present between 0.01 and 0.1percent by weight; and the corrosion inhibitor includes at least onemember selected from the group consisting of: (a) urea; (b) corn steepliquor; (c) glycerol; and (d) organic sulfonate.
 11. The composition ofclaim 10, wherein the pH is between 6.5 and 7.5.
 12. The composition ofclaim 8, wherein the anionic polyacrylamide has CAS number 25987-30-8.13. A liquid fertilizing composition, consisting essentially of:Constituent Weight % ammonium chloride at least 16.5 anionicpolyacrylamide 0.5-1.0 corrosion inhibitor effective amount waterbalance

wherein the anionic polyacrylamide comprises at least one monomeric unitof acrylamide and at least one monomeric unit of acrylic acid or saltthereof, and wherein the anionic polyacrylamide is prepared bycopolymerization of acrylamide and acrylic acid or salt thereof.
 14. Thecomposition of claim 13, wherein the corrosion inhibitor includes atleast one member selected from the group consisting of: (a) urea; (b)corn steep liquor; (c) glycerol; and (d) organic sulfonate.
 15. Thecomposition of claim 13, wherein the pH is between 6 and 7.5.
 16. Thecomposition of claim 13, wherein the pH is between 4 and 8.5.
 17. Thecomposition of claim 13, wherein the anionic polyacrylamide has CASnumber 25987-30-8.